Image processing apparatus and image processing method

ABSTRACT

An image processing apparatus and an image processing method processing a graphic image are provided. An image processing apparatus including: a display unit; a first image output unit which outputs a first image signal; a second image output unit which outputs a second image signal and a transparency information with respect to the second image signal; an image mixing unit which outputs a third image signal mixing the first image signal and the second image signal by using the transparency information; an image processing unit which processes the third image signal to output to the display unit; and a control unit which extracts the transparency information from the second image output unit, and outputs a position information about which the second image signal is displayed in the display unit based on the extracted transparency information to the image processing unit.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of application Ser. No. 12/721,670 filed Mar. 11,2010, which claims priority from Korean Patent Application No.10-2009-0084603, filed on Sep. 8, 2009, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

An apparatus and a method consistent with exemplary embodiments relateto an image processing apparatus and an image processing method, andmore particularly, to an image processing apparatus and an imageprocessing method for processing a graphic image.

Description of the Related Art

If a graphic image such as an on screen display (OSD) is overlapped overa video image displayed as a main image, an image processing apparatusperforms an alpha-blending with respect to the video image and thegraphic image by using an alpha information. The alpha information is avalue used in processing the alpha-blending, and means to mix a color ofa background, and a color of an image overlapped thereover.

When processing an image, for example, when presuming a movement orconverting a frame rate, it is necessary to discern a graphic image anda video image to reduce an error due to an image mixture.

If a graphic image and a video image is discerned with a method ofregarding or presuming a specific area as a graphic video, a clear graspwith respect to an overlapped area is impossible, thereby causing anerror in an image processing, and deteriorating an image quality.

SUMMARY OF THE INVENTION

Illustrative, non-limiting embodiments overcome the above disadvantagesand other disadvantages not described above. Also, the present inventionis not required to overcome the disadvantages described above, and anillustrative, non-limiting embodiment of the present invention may notovercome any of the problems described above.

Accordingly, it is an aspect of the exemplary embodiments to provide animage processing apparatus and an image processing method processing animage based on a correct position information of a graphic image.

Another aspect of the exemplary embodiments is to provide an imageprocessing apparatus and an image processing method determining aposition information of a graphic image based on a transparencyinformation.

Still another aspect of the exemplary embodiments is to provide an imageprocessing apparatus and an image processing method processing an imagebased on a transparency information.

According to an aspect of the exemplary embodiments, there is providedan image processing apparatus including: a display unit; a first imageoutput unit which may output a first image signal; a second image outputunit which may output a second image signal and a transparencyinformation with respect to the second image signal; an image mixingunit which may output a third image signal mixing the first image signaland the second image signal by using the transparency information; animage processing unit which may process the third image signal to outputto the display unit; and a control unit which may extract thetransparency information from the second image output unit, and mayoutput a position information about which the second image signal isdisplayed in the display unit based on the extracted transparencyinformation to the image processing unit.

The control unit may output to the image processing unit a transparencymap representing whether there exists the transparency information withrespect to each pixel.

The control unit may compare the transparency information with apredetermined reference value, and may output to the image processingunit a transparency map with respect to the position of the second imagesignal generated based on a comparison result.

The control unit may classify the transparency information into apredetermined group depending on a transparency degree, and may outputto the image processing unit a transparency map with respect to theposition of the second image signal based on a classification result.

The image processing apparatus may further comprise a user interface fordetermining the reference value.

The image processing unit may comprise a frame rate converting unitwhich converts a frame rate of the third image signal.

If the third image signal is a two dimensional image, the imageprocessing unit may include an image converting unit which converts thetwo dimensional image into a three dimensional image signal.

The first image signal may include a video image, and the second imagesignal may include a graphic image.

The image processing apparatus may further include a broadcastingreceiving unit which receives a broadcasting signal, wherein the firstimage signal may include a broadcasting image signal included in thebroadcasting signal, and the second image signal may include a datasignal included in the broadcasting signal.

According to another aspect of the exemplary embodiments, there isprovided a control method of an image processing apparatus, including:receiving a first image signal, a second image signal and a transparencyinformation with respect to the second image signal; mixing the firstimage signal and the second image signal by using the transparencyinformation; generating a position information by which the second imagesignal is displayed in a display unit based on the transparencyinformation; and processing the mixed image signal by using the positioninformation.

The generating the position information may include generating atransparency map representing whether there exists the transparencyinformation with respect to each pixel.

The generating the position information may include comparing thetransparency information with a predetermined reference value, andgenerating a transparency map with respect to the position of the secondimage signal generated based on a comparison result.

The generating the position information may include classifying thetransparency information into a predetermined group depending on atransparency degree, and generating a transparency map with respect tothe position of the second image signal based on a classificationresult.

The processing the mixed image signal may include converting a framerate of the mixed image signal.

The first image signal may include a video image, and the second imagesignal comprises a graphic image.

BRIEF DESCRIPTION OF THE DRAWINGS

The aspects of the exemplary embodiments will become apparent and morereadily appreciated from the following description of the exemplaryembodiments, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a control block diagram of an image processing apparatusaccording to an exemplary embodiment;

FIG. 2 illustrates an image according to each stage of the imageprocessing apparatus in FIG. 1;

FIG. 3 illustrates a transparency map by a control unit in FIG. 1;

FIG. 4 illustrates another transparency map by the control unit in FIG.1;

FIG. 5 is a control block diagram of an image processing apparatusaccording to another exemplary embodiment of the present invention;

FIG. 6 illustrates a display image according to the image processingapparatus in FIG. 5; and

FIG. 7 is a control flowchart for describing a control method of animage processing apparatus according to an exemplary embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Reference will now be made in detail to exemplary embodiments, examplesof which are illustrated in the accompanying drawings, wherein likereference numerals refer to like elements throughout. The exemplaryembodiments are described below so as to explain the present inventionby referring to the figures. The present invention may, however, beembodied in many different forms and should not be construed as beinglimited to the embodiments set forth therein; rather, these embodimentsare provided so that this disclosure will be thorough and complete, andwill fully convey the concept of the present invention to those skilledin the art. Repetitive description with respect to like elements ofdifferent embodiments may be omitted for the convenience of clarity.

FIG. 1 is a control block diagram of an image processing apparatusaccording to an exemplary embodiment, and FIG. 2 illustrates an imageoutput from each configuration block of the image processing apparatusin FIG. 1. As shown therein, the image processing apparatus includes aplurality of image output units 10 and 20, an image mixing unit 30mixing an image output from the plurality of image output units 10 and20, an image processing unit 40 processing a mixed image, a display unit50, and a control unit 60 controlling, at least, the image processingunit 40 and the display unit 50. The image processing apparatusaccording to the exemplary embodiment includes a display apparatuscapable of processing a plurality of images in different layers, and mayinclude a computer system, a television, various terminals, etc.

The first image output unit 10 outputs a first image signal, and thesecond image output unit 20 outputs a second image signal. The firstimage signal and the second image signal are formed in different layers,mixed, and then displayed in the display unit 50. The first image signalmay be an image signal formed in a subordinate layer displaying a videoimage, that is a video layer, and the second video signal may be agraphic image included in a graphic layer such as an on screen display(OSD), sub picture, a caption, etc. overlapped over the video layer.

The first image output unit 10 and the second image output unit 20 mayinclude an image source outputting an image to the image mixing unit 30.For example, the first image output unit 10 and the second image outputunit 20 may include a broadcasting receiving unit outputting abroadcasting image, a network interface such as an internet, aconnecting unit receiving a digital versatile disk (DVD) image, a gamemodule outputting a game image, a user interface (UI) generating unitgenerating a graphic user interface such as an OSD, etc. The first imageoutput unit 10 and the second image output unit 20 may have a physicallyindependent configuration, or may be provided as a single configurationas long as it is a configuration capable of outputting different imagesoverlapped to be displayed.

If the second image signal output from the second image output unit 20is a graphic image overlapped over a video image, the second imageoutput unit 20 further outputs to the image mixing unit 30 atransparency information representing a transparency degree. Thistransparency information is referred to an alpha value, and correspondsto a fourth color element corresponding to an opacity degree of thesecond image signal although not shown. Typically, the alpha value is a8-bit data capable of discerning a transparency degree of 0 to 255.

The image mixing unit 30 performs an alpha blending mixing an imagebased on the first image signal, the second image signal, and thetransparency information. Hereinafter, an image signal mixed in theimage mixing unit 30 and output to the image processing unit 40 will bereferred to a third image signal. As shown in FIG. 2, if a first imagesignal I in which a house is illustrated, and a second image signal IIwith respect to a leaf included in a circle are input to the imagemixing unit 30, a third image signal III in which the house and the leafare overlapped is output from the image mixing unit 30. In an overlappedarea IV in which the first image signal I and the second image signal IIare overlapped, a degree by which the first image signal I is displayedvaries depending on the transparency information. For example, the housebecomes to be displayed more clearly as the transparency increases, andclarity of the house becomes deteriorated and the second image signal IIbecomes to be displayed more clearly as the transparency decreases. Theoverlapped area IV in which an object of the first image signal I andthe second image signal II are overlapped each other, and a boundarypart of the second image signal II overlapped with the first imagesignal I correspond to an area in which an error is likely to frequentlyhappen in an image processing of estimating a movement or forming aninterpolation image. To prevent this error, a position information aboutwhere the second image signal is displayed becomes very important in animage processing after mixing. A method by which the image mixing unit30 mixes an image includes known algorithms, and is not defined in aspecific method.

The image processing unit 40 corresponds to a post-processing blockprocessing the third image signal to be finally displayed in the displayunit 50. For example, the image processing unit 40 may estimate amovement of the third image signal to interpolate an image, or mayinclude a frame rate converting unit converting a frame rate. Also, ifthe third image signal is a two dimensional image, the image processingunit 40 may include an image converting unit converting this into athree dimensional image.

The display unit 50 displays an image signal processed in the imageprocessing unit 40. The display unit 50 may include a liquid crystaldisplay (LCD) panel including a liquid crystal, an organic lightemitting diode (OLED) panel including an organic light emitting element,or a plasma display panel (PDP), and a panel driving unit driving thepanel.

The control unit 60 extracts the transparency information from thesecond image output unit 20, and outputs a position information V (seeFIG. 2) to the image processing unit 40 based on the extractedtransparency information. The illustrated position information meansinformation about a pixel in which the second image signal II isdisplayed in the display unit 40. As described above, if the secondimage signal II is overlapped over the first image signal I, it isnecessary for the image processing unit 40 to correctly determine theposition with respect to the second image signal II. Also, since animage processing may vary depending on the transparency degree, todetermine a correct transparency information may be an important factorfor the movement estimation and the image interpolation.

Conventionally, since the position of the second image signal isdetermined by expecting the position or the shape in which the secondimage signal is likely to exist, or by presuming a still image, an errorhappening rate is high in a movement estimation and interpolating aframe. Especially, if the first image signal is a motion picture, or ifthe second image signal is not a typical shape, it is difficult todetermine the position and it leads to an image processing error.

The control unit 60 according to the present exemplary embodimentsupplies a correct position information of the second image signal II tothe image processing unit 40 by using the transparency information. Thecontrol unit 60 may supply all of the transparency information to theimage processing unit 40, or may supply a part of the transparencyinformation, or may supply only information about a position but thetransparency information. In any case, the control unit 60 suppliesinformation about an area in which the second image signal II does notexist, and information about an area in which the second image signal IIexists in a map type so that the image processing unit 40 can easilydetermine the position of the second image signal II.

FIGS. 3 and 4 illustrate a transparency map by the control unit 60. FIG.3 illustrates a transparency map representing whether there exists thetransparency information by each pixel. The control unit 60 may generateinformation that “1” is referred to an area in which there is thetransparency information, that is, an area in which the second imagesignal II is overlapped with the first image signal I, and “0” isreferred to an area in which there is only the first image signal I byeach pixel to output to the image processing unit 40. In this case,since the amount of data of the position information output to the imageprocessing unit 40 becomes reduced in comparison to the case that thetransparency information itself is output, a data processing speedincreases.

According to another exemplary embodiment, the control unit 60 maycompare the transparency information with a predetermined referencevalue, and may generate a transparency map based on a comparison result.For example, if the transparency is very high so that an image isdisplayed like there is no second image signal II, although there istransparency information, the control unit 60 may output “0” althoughthere is the second image signal II. In this case, the control unit 60may further include a comparing unit comparing the transparencyinformation with a reference value. This reference value may bedetermined to be various levels, and it is possible to selectively omitto apply the reference value.

FIG. 4 illustrates a transparency map in the case that the referencevalue exists in plural. It may be applied to the case that thetransparency information about the second image signal II has not asingle value but a partially different value, and the case that thesecond image signal II having a different transparency informationexists not continuously but intermittently. For example, a transparencydegree of a part of the second image signal II may be 70%, and that ofthe remained part thereof may be 20%. In this case, the image processingunit 40 may process an image by using different algorithms or variablesdepending on the transparency degree. With a consideration of thispoint, the control unit 60 may add the position information of thesecond image signal II to supply the transparency information to theimage processing unit 40. The control unit 60 may classify thetransparency information into a predetermined group depending on thetransparency degree, and may generate a transparency map with respect tothe position of the second image signal II based on a classified result.As shown therein, “0” may be output as the position information withrespect to an area in which there is only the first image signal I, anda group in which the transparent information of the second image signalII is less than a first reference value. “1” may be output as theposition information with respect to a group in which the transparentinformation of the second image signal II exists between the firstreference value and a second reference value which is bigger than thefirst reference value. “2” may be output as the position informationwith respect to a group in which the transparent information of thesecond image signal II is more than the second reference value. Thenumber of the group and the number of the reference value are not fixed,and may be determined with a consideration of a processing ability ofthe image processing unit 40 and a data processing speed of thecomparing unit.

The number used in the above transparency map is just a number referredto for a convenient description, and a data value or a data type whichthe control unit 60 actually outputs is not defined thereto. Also, thepresent invention may be applied to the case that overlapped images maybe more than two.

FIG. 5 is a control block diagram of an image processing apparatusaccording to another exemplary embodiment. As shown therein, the imageprocessing apparatus may include a television, a set top box, etc.including a broadcasting receiving unit 11, and includes a frame rateconverting unit 41 converting a frame rate of a broadcasting signal, anda user interface 70 for determining a reference value. Repetitivedescription with respect to the above configurations is omitted.

The broadcasting receiving unit 11 may include an antenna, a tuner, etc.receiving a broadcasting signal. A received broadcasting signal mayinclude a broadcasting image signal corresponding to a broadcastingcontent, and a data signal corresponding to a data broadcasting. In thiscase, the broadcasting image signal corresponds to the first imagesignal according to the above exemplary embodiment, and the data signalcorresponds to the second image signal. The broadcasting receiving unit11 may further include a demultiplexer dividing a broadcasting imagesignal and a data signal from a broadcasting signal.

FIG. 6 illustrates a display image displayed in the display unit 50. Asecond image signal II which is a data signal is overlapped over a firstimage signal I. In case of the data broadcasting, information related toa broadcasting content, weather, news, a traffic information, etc. areoverlapped over a broadcasting signal and to be displayed in a captiontype.

The frame rate converting unit 41 corresponds to the image processingunit of the exemplary embodiment described above, and the display unit50 may include a liquid crystal panel.

The user interface 70 is a configuration for determining a referencevalue used to a position information which the control unit 60 suppliesto the frame rate converting unit 41. The user interface 70 may includea user input unit for a user input, a GUI (graphic user interface) unitgenerating and displaying a GUI, etc. The reference value may bedetermined to be a constant value during a manufacturing process of animage processing apparatus, and may be changed or deleted by a userafter the manufacturing process.

FIG. 7 is a control flowchart for describing a control method of animage processing apparatus according to an exemplary embodiment. Acontrol method of an image processing apparatus according to the presentexemplary embodiment will be described by referring to FIG. 7.

At first, the image mixing unit 30 receives a first image signal, asecond image signal and a transparency information with respect to thesecond image signal (S10), and mixes the first image signal and thesecond image signal by using the transparency information (S20).

The control unit 60 extracts the transparency information from thesecond image output unit 20, and generates a position information bywhich the second image signal is displayed in the display unit 50 basedon the transparency information (S30). The position information mayinclude a transparency map representing whether there is thetransparency information with respect to each pixel, a transparency mapbased on a transparency information compared a reference value, atransparency map based on a transparency information classified into agroup depending on a transparency degree, etc. Also, all or a part ofthe transparency information may be output to the image processing unit40 as the position information.

The image processing unit 40 processes an image signal by using themixed third image signal III and the position information (S40), anddisplays this in the display unit 50.

As described above, if at least two image layers are overlapped,exemplary embodiments supplied correct position information andtransparency information with respect to the overlapped image signal.

As described above, exemplary embodiments provide an image processingapparatus and an image processing method capable of processing an imagebased on a correct position information of a graphic image.

Also, exemplary embodiments provide an image processing apparatus and animage processing method capable of determining a position information ofa graphic image based on a transparency information.

Also, exemplary embodiments provide an image processing apparatus and animage processing method capable of processing an image based on atransparency information.

Although a few exemplary embodiments of the present invention have beenshown and described, it will be appreciated by those skilled in the artthat changes may be made in these exemplary embodiments withoutdeparting from the principles and spirit of the invention, the scope ofwhich is defined in the appended claims and their equivalents.

What is claimed is:
 1. An image processing apparatus comprising: animage mixing unit which receives a first image signal and a second imagesignal, mixes the first image signal and the second image signal, andoutputs a third image signal as a result of the mixing; an imageprocessing unit which processes the third image signal and outputs theprocessed third image signal to a display unit; and a control unit whichoutputs to the image processing unit position information regarding thedisplaying of the second image signal in the display unit.
 2. The imageprocessing apparatus according to claim 1, further comprising: a firstimage output unit which outputs the first image signal; and a secondimage output unit which outputs the second image signal and transparencyinformation with respect to the second image signal, wherein the imagemixing unit mixes the first image signal and the second image signal byusing the transparency information.
 3. The image processing apparatusaccording to claim 2, wherein the control unit extracts the transparencyinformation from the second image output unit and generates the positioninformation of the second image signal based on the extractedtransparency information.
 4. The image processing apparatus according toclaim 3, wherein the control unit outputs the position informationincluding a transparency map representing presence of transparencyinformation with respect to each pixel of the second image signal to bedisplayed.
 5. The image processing apparatus according to claim 3,wherein the control unit compares the transparency information with apredetermined reference value, and outputs the position informationincluding a transparency map with respect to the position of the secondimage signal, the transparency map generated based on a result of thecomparison.
 6. The image processing apparatus according to claim 5,further comprising: a user interface for determining the referencevalue.
 7. The image processing apparatus according to claim 3, whereinthe control unit classifies the transparency information into apredetermined group depending on a transparency degree, and outputs theposition information including a transparency map with respect to theposition of the second image signal, the transparency map generatedbased on a result of the classification.
 8. The image processingapparatus according to claim 1, wherein the image processing unitcomprises a frame rate converting unit which converts a frame rate ofthe third image signal.
 9. The image processing apparatus according toclaim 1, wherein the image processing unit comprises an image convertingunit which converts a two dimensional image into a three dimensionalimage signal, wherein if the third image signal is a two dimensionalimage, the image converting unit converts the two dimensional image intoa three dimensional image signal.
 10. The image processing apparatusaccording to claim 1, wherein the first image signal comprises a videoimage, and the second image signal comprises a graphic image.
 11. Theimage processing apparatus according to claim 1, further comprising: abroadcasting receiving unit which receives a broadcasting signal,wherein the first image signal comprises a broadcasting image signalincluded in the broadcasting signal, and the second image signalcomprises a data signal included in the broadcasting signal.
 12. Acontrol method of an image processing apparatus, comprising: receiving afirst image signal and a second image signal; mixing the first imagesignal and the second image signal; generating position informationregarding the displaying of the second image signal in a display unit;and processing the mixed image signal by using the position information.13. The control method of the image processing apparatus according toclaim 12, further comprising: receiving transparency information withrespect to the second image signal.
 14. The control method of the imageprocessing apparatus according to claim 13, wherein the generatingposition information comprises generating the position informationincluding a transparency map representing presence of the transparencyinformation with respect to each pixel of the second image signal to bedisplayed.
 15. The control method of the image processing apparatusaccording to claim 13, wherein the generating position informationcomprises comparing the transparency information with a predeterminedreference value, and generating the position information including atransparency map with respect to the position of the second imagesignal, the transparency map generated based on a result of thecomparison.
 16. The control method of the image processing apparatusaccording to claim 13, wherein the generating position informationcomprises classifying the transparency information into a predeterminedgroup depending on a transparency degree, and generating the positioninformation including a transparency map with respect to the position ofthe second image signal, the transparency map generated based on aresult of the classification.
 17. The control method of the imageprocessing apparatus according to claim 12, wherein the processing themixed image signal comprises converting a frame rate of the mixed imagesignal.
 18. The control method of the image processing apparatusaccording to claim 12, wherein the first image signal comprises a videoimage, and the second image signal comprises a graphic image.
 19. Thecontrol method of the image processing apparatus according to claim 12,wherein the first image signal and the second image signal are receivedfrom a broadcasting signal, the first image signal comprises abroadcasting image signal included in the broadcasting signal, and thesecond image signal comprises a data signal included in the broadcastingsignal.